I've done this before, several times. I've had to do it on the cheap and I've had the time and $$ to do it well. You can get surprisingly good results on the cheap. Doing it on the cheap, though, will require some work for it to look good, and the work to make it look good will also make it last.
Doing It Right: The suggestions for powder coating are spot on.
I have had wheels painted with duPont Imron and also with base and clear coat.
On The Cheap: Figure this will cost you $25 to $30, plus some time. It assumes that the wheels (rims) are in good shape and the outer edges are not rusty. If there's rust, you'll need to add sanding after the SOS pad part and spray can priming before the painting.
This is easier if you are planning to replace the tires right away. You can save the masking step. You can do this one tire/wheel at a time, and you don't have to do them all at once. The car might look a little odd until you are done. (1) Buy two cans of regular (not water-base) spray paint in the color you like, and a can of spray clear. I prefer Rust-O-Leum products for this. Read the instructions and follow them. Practice on something first. (2) Remove the wheel cover. You will probably have to take the tire and wheel off the car. Mark the tire where the wheel weights are and remove them. Thoroughly clean both sides of the tire and wheel with warm to hot water and a sponge or rag. (2) With an SOS pad, clean the area that will need to be painted. (3) Wipe the area dry with quality paper towels or lint-free cotton rags. Consider wiping down with denatured alcohol and letting air dry. (4) Mask the tire with green or beige masking tape. (5) Paint the outer 1 or 2 inches of the wheel in several light coats, with the spray clear last. Let dry for several hours. Overnight is way better. (6) If you have to, put the tire/wheel back on the car to park it over night, which you can sort of combine with step 5. (7) carefully tap the wheel weights back on where they were and put baby moon hubcaps on. Test drive for wheel bounce to see if you need to have a tire shop do the balance. It would be best to wait about 5 days for that if you can stand the bounce because the paint will still be a bit soft.
PM me if you have more questions. This can actually look nice.
